Offset device.



Patented Nov. 26, l90l. 0. ROESEN.

OFFSET DEVICE.

UNITED STATES PATENT OFFICE.

OSCAR ROESEN, OF NEW YORK, N. Y., ASSIGNOR, BY DIRECT AND MESNEASSIGNMENTS, TO ROBERT HOE AND CHARLES W. CARPENTER, OF NEW YORK, N. Y.,UNDER THE FIRM-NAME OF R. HOE AND COMPANY.

OFFSET DEVICE.

SPECIFICATION forming part of Letters Patent No. 687,575, dated November26, 1901. Application filed December 8, 1899- Serial No. 739,587. (Nomodel.)

To all whom, it may concern:

Be it known that LOSGAR ROESEN, acitizen of the United States, residingat New York, county of New York, and State of New York, have inventedcertain new and useful Improvements in Offset Devices, fully describedand represented in the following specification and the accompanyingdrawings, forming a part of the same.

This invention relates to certain improvements in devices for preventingoffset.

In perfecting printing machines if the freshly-printed web or sheetcomes in contact with the covering or tympan on the impression-surfaceof the couple making the perfecting impression the ink from thefreshlyprinted paper comes off onto the tympan of the said surface, andafter a certain amount has been thus deposited thereon it begins to setback on or, as it is termed in the art, to offset onto the sheet. Thissmuts the sheet and seriously interferes with good printing, especiallyin fine bookwork and in heavy cutwork,where large amounts of ink areused. Many devices have been used to prevent this offset. In the morepractical forms of such devices an absorbent surface is used, which iseither carried by the impression cylinder which receives the offset orruns between it and the web, this surface being either an oifset-web,which is run constantly through the machine with the material to beprinted, or a tympan-web, which is carried by reels located inside ofthe impression-cylinder and is wound from one to the other with more orless frequency during the printing operation.

The devices before adverted to are objectionable in that they requiremore or less complicated mechanism for their successful operation. Theyalso remove a certain portion of the ink from the printed sheet, thisbeing especially objectionable in fine bookwork and in cutwork of alldescriptions, where it is very desirable in order to produce animpression having the proper finish and luster that as much as possibleof the ink placed on the sheet by the printing-surface be retained andallowed to dry thereon.

The object of this invention is to produce an improved and practicaloffset surface which shall do away with the complicated mechanisms nowcommonly used for this purpose.

With these and other objects in view the invention consists in certainconstructions and in certain parts, improvements, and combinations, suchas will be hereinafter described, and fully pointed out in the claimshereunto appended.

In the accompanying drawings, Figure 1 is a detail elevation of so muchof a printingmachine as is necessary to illustrate my in- Vention. Fig.2 is a sectional elevation of an improved cylinder provided with myimproved form of offset device.

Referring to the drawings, Fig. 1 illustrates diagrammatically anysuitable form of perfecting printing-machine, the machine herein shownbeing of the rotary type. The frame of the machine is indicated at 1,and the said frame supports a rotary printing-couple of the ordinarytype, the plate or printing-cylinder of said couple being marked 2 andthe impression-cylinder 3. The printing-cylinder of the second orperfecting couple is marked 4, and the impression-cylinder of thiscouple is marked 5. The web W to be printed is shown as entering betweenthe cylinders 2 and 3 and being printed by them on one side, after whichit is passed between the cylinders 4 5, from which it receives theimpression on the other side. A suitable inking mechanism, which neednot be herein described, as it may be of any form, is shown. The secondimpression cylinder, against which the freshly-printed surface of theweb comes, is provided with a porous surface 6,

which when moistened becomes ink-repellingg 'f is presented to thepassing printedweb or sheet. This surface will preferably be metallicand preferably consist of aluminium, as this metal is so porous that itreadily absorbs the moisture which is applied thereto, and thisabsorption of moisture renders it ink-repelling. Other surfaces might beused-such, for instance, as zincbut aluminium is preferred, not only onaccount of its porosity, but also because on account of its softness andductility it readily adapt-s itself to any unevenness in the height ofthe printing-surfaces such,for instance,as those produced byunderlaying. While this metallic surface may, if desired, be applieddirectly to the surface of the cylinder, it will preferably, in order toimprove the impression qualities, have interposed between it and thecylinder an elastic surface 7 of some suitable material. This surfacemay consist of paper or any other suitable material, but preferably willconsist of rubber.

Any suitable means may be provided for holding the metallicoffset-surface and its supporting-surface in position on the cylinder.In the machine shown the surfaces 6 and 7 are shown as secured at oneend in the ordinary gap by being passed over pins 8. Fingers ,9, mountedon a shaft 10 and held in position by the springs 11, serve to hold thesheets on the pins. The rubber or other sup- .porting sheet ispreferably secured at its other end by being passed around a reel 12,which is operated in any suitable manner. The aluminium or other porousoffset surface is held at its opposite end in clamps 13, mounted on a'shaft 14. This holding device may be of any suitable construction, butwill preferably be of the construction shown in the patent toSpalckhavergranted August 1, 1899, No. 629,930, inasmuch as a clamp ofthis description. permits of a very narrow opening or gap in theimpression-cylinder.

The aluminium or other metallic sheet will preferably be prepared inmuch the same way as such sheets are usually prepared forprinting-surfaces-that is to say, its surface will be etched and thenroughened by sand-blasting or in any other suitable manner.

Although any suitable etching-acid may be used, the acid employed willpreferably consist of a weak solution of phosphoric acid, inasmuch asthe purpose of the acid in this case is to absolutely remove all thegrease from the surface of the aluminium plate, so that the ink will notadhere thereto. This will be accomplished by the solution of phosphoricacid, and this acid does not bite the surface of the plate so'much asnitric acid, which is the etching-acid ordinarily used.

Damping devices, which may be of any suitable description, will beemployed to keep the surface wet. In the machine shown they consist of awater-trough 15, having a fountain-roll 16. A suitable ductor-roll 17takes the water from the roll 16 and delivers it to thedistributing-rolls 18, by which it is applied to the aluminium or othermetallic surface.

Aluminium and some other metallic plates are, as is well known, used forprinting-surfaces, those parts of the plates which carry the designbeing prepared to take the ink by having the design transferred to themby greasy inks, the remainder of the plate or surface being etched anddampened, so as to repel the ink. It is obvious, therefore, that if theentire surface of such plates be treated so as to be ink-repellent noink will adhere from the printed sheet as it runs in contact therewith.d

An impression-cylinder which is so located as to come in contact withthe freshly-printed side of a sheet or web if protected in the mannerdescribed will not receive any ink from such sheet or web. It 'cannottherefore offset onto the web or succeeding sheets, and, furthermore,since no ink is taken from the printed sheets or web by the surface ofthe cylinder a greatly-improved product will result.

Vhile the cylinder will preferably be prepared by placing a rubber orother elastic covering thereon and then securing a thin sheet ofaluminium or other ink-repelling metal thereto, it will be understoodthat the invention is not necessarily limited to such a construction.For instance, the rubber or other elastic covering may have a thincoating of metal foil applied to its surface, or a metal surface may beapplied in any other suitable or desirable manner, the'essential featureof the invention being to provide a cylinder which is to come in contactwith an inked sheet with a suitable surface of porous material,preferably metal, which when dampened becomes ink-repelling.

What I claim is- 1. An impression device for printing presses comprisinga suitable base, the base having a separate impression-s11 rface orcoating thereon which when moistened becomes ink-repelling,substantially as described.

2. An anti-offset impression device comprising a porous or grainedsurface,.which surface when moistened becomes ink-repelling,substantially as described.

3. An anti-offset impression device comprising a porous or grainedmetallic surface, which surface when moistened becomes inkrepelling,substantially as described.

4. An anti-offsetimpression device comprising a gummed and etchedsurface, which surface when moistened becomes ink-repelling,substantially as described. I

5. An anti-offsetimpression device co mprising a gummed and etchedmetallic surface, which surface when moistened becomes inkrepelling,substantially as described.

6. An anti-offset mechanism comprising an impression device having aporous surface which when moistened becomes ink-repelling, and means formoistening the impressionsurface, substantially as described.

IIO

10. An anti-offset impression device com prising a gummed and. etchedporous or grainedmetallic surface, which surface when moistenedbecomesink repelling, substantially as described.

11. An anti-ofiset mechanism comprising an impression device having agummed and etched porous surface which when moistened becomesink-repelling, and means for moistening the impression surface,substantially as described. 1

12. An-offset device consisting of a cylinder having a porous surfacewhich when moistened becomes ink-repelling, substantially as described.

13. An offset device consisting of a cylinder having a porous metallicsurface which when moistened becomes ink repelling, substantially asdescribed.

14. An olfset device consisting of a cylinder having an aluminiumsurface,substantially as described. I

15. An ofiset device consisting of a cylinder having a porous surfacewhich when moistened becomes ink-repelling, and a suitable backing undersaid surface, substantially as described.

16. An offset device consisting of a cylinder having a porous metallicsurface which when moistened becomes ink-repelling, and a suit ablebacking under said surface, substantially as described.

17. An offset device consisting of a cylinder having an aluminiumsurface and a suitable hacking under said surface, substantially asdescribed.

18. In an offset device, the combination with the cylinder, of means forholding a suitable rubber backing thereon, and means for securing aporous surface which when moistened becomes ink-repelling in positionover the backing, substantially as described.

19. In an offset device, the combination with the cylinder, of means forholding a suitable rubber backing thereon, and means for securing asheet of aluminium in position over the backing, substantially asdescribed.

20. An offset device including a cylinder having an etched porousmetallic surface which when moistened becomes ink-repelling,substantially as described.

21. In an ofiset mechanism, the combination with a cylinder having aporous surface, of means whereby the surface is kept dampened during theprinting operation, substan tially as described.

22. In an offset mechanism, the combination with a cylinder having aporous metallic surface, of means whereby the surface is kept dampduring the printing operation, substan tially as described.

23. In an ofiset mechanism, the combination with a cylinder having anetched porous metallic surface, of means whereby the sur face is keptdamp during the printing operation, substantially as described.

24:. In an offset mechanism, the combination with a cylinder having analuminium sur= face, of means whereby the surface is kept damp duringthe printing operation, substantially as described.

25. In an ofiset mechanism, the combina= tion with a cylinder having anetched aluminium surface, of means whereby the sur face is kept dampduring the printing opera= tion substantially as described.

26. In an ofiset mechanism, the combination with a cylinder havingaporous metallic surface, of suitable water-distributing de= vicesrunning in contact with said surface, substantially as described.

27. In an ofiset mechanism, the combination with a cylinder having analuminium surface, of suitable water-distributing devices running incontact with said surface, substantially as described.

28. In an oflset mechanism, the combination with a cylinder having asuitable elastic backing, of an etched aluminium surface, means forholding the backing and the surface in position, and suitable clampingdevices, substantially as described.

29. In an offset mechanism the combination with a cylinder having arubber backing, of an etched aluminium surface, means for holding thebacking and the surface in position, and suitable clamping devices, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

OSCAR ROESEN.

Witnesses:

OTTO L. RAABE, H NRY S. MOUNT.

